The first two spools are done; it's taking quite a while because I'm spinning pretty fine at about 90 WPI (using Alden Amos' "pack to refusal" technique). For the third spool I've decided to try Alden's "carding and spinning oil emulsion" recipe, I made up a batch and sprayed it on a small part of the remaining commercial roving, and put it in a ziplock to condition for an hour or so. Now I'm spinning it up.
Result: much, much easier to spin fine!!
The roving feels oily and weird to spin at first, but the emulsion is letting the nebs in the commercial roving almost dissolve. It acts kind of like a hair conditioner, ironing out the tangles, and making for much smoother spinning. Of course, you have to scour it out of your yarn when it's finished, but washing your finished yarn to set the twist is normal, anyways. Certainly on my short and springy Southdown fiber, this is working very well.
I'm not going to publicize Alden's copyrighted recipe, you will need to get his book for that, but it's a pretty simple concoction of a tiny amount of soap and washing soda, used to emulsify a bunch of olive oil in soft (not hard) water. It makes a stable solution that you don't need to shake, and that keeps. I've read some people advocate a spritz of baby oil in a water sprayer, that might also work but it isn't a very good emulsion.
[Southdown on top; 1 ply of commercial laceweight on bottom for comparison]
I've also started rewinding my finished singles onto new spools, using a cheap chopstick in a hand drill set on "low", so that the spools are evenly wound while they rest until I'm ready to ply. I'm working on getting a tensioned lazy kate, because I think trying to ply singles that are this thin is going to be a tangly nightmare without one!
[drill + chopstick as spool winder]
I'm a big advocate of rewinding. It means I don't have to take the bobbin off of the spinning wheel (which, for my new double-drive setup, is a huge plus). Also I don't need to wind off onto a bobbin - any spool-type device will do. Finally, rewinding gets rid of all the "pigtails" in the singles and makes sure they are under consistent tension. For thin singles, this makes for a much easier plying experience...